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1/*
2 * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
3 * Copyright (C) 2006 Andrey Volkov, Varma Electronics
4 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the version 2 of the GNU General Public License
8 * as published by the Free Software Foundation
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20#include <linux/module.h>
21#include <linux/kernel.h>
22#include <linux/slab.h>
23#include <linux/netdevice.h>
24#include <linux/if_arp.h>
25#include <linux/can.h>
26#include <linux/can/dev.h>
27#include <linux/can/netlink.h>
28#include <net/rtnetlink.h>
29
30#define MOD_DESC "CAN device driver interface"
31
32MODULE_DESCRIPTION(MOD_DESC);
33MODULE_LICENSE("GPL v2");
34MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
35
36#ifdef CONFIG_CAN_CALC_BITTIMING
37#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
38
39/*
40 * Bit-timing calculation derived from:
41 *
42 * Code based on LinCAN sources and H8S2638 project
43 * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
44 * Copyright 2005 Stanislav Marek
45 * email: pisa@cmp.felk.cvut.cz
46 *
47 * Calculates proper bit-timing parameters for a specified bit-rate
48 * and sample-point, which can then be used to set the bit-timing
49 * registers of the CAN controller. You can find more information
50 * in the header file linux/can/netlink.h.
51 */
52static int can_update_spt(const struct can_bittiming_const *btc,
53 int sampl_pt, int tseg, int *tseg1, int *tseg2)
54{
55 *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
56 if (*tseg2 < btc->tseg2_min)
57 *tseg2 = btc->tseg2_min;
58 if (*tseg2 > btc->tseg2_max)
59 *tseg2 = btc->tseg2_max;
60 *tseg1 = tseg - *tseg2;
61 if (*tseg1 > btc->tseg1_max) {
62 *tseg1 = btc->tseg1_max;
63 *tseg2 = tseg - *tseg1;
64 }
65 return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
66}
67
68static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
69{
70 struct can_priv *priv = netdev_priv(dev);
71 const struct can_bittiming_const *btc = priv->bittiming_const;
72 long rate, best_rate = 0;
73 long best_error = 1000000000, error = 0;
74 int best_tseg = 0, best_brp = 0, brp = 0;
75 int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
76 int spt_error = 1000, spt = 0, sampl_pt;
77 u64 v64;
78
79 if (!priv->bittiming_const)
80 return -ENOTSUPP;
81
82 /* Use CIA recommended sample points */
83 if (bt->sample_point) {
84 sampl_pt = bt->sample_point;
85 } else {
86 if (bt->bitrate > 800000)
87 sampl_pt = 750;
88 else if (bt->bitrate > 500000)
89 sampl_pt = 800;
90 else
91 sampl_pt = 875;
92 }
93
94 /* tseg even = round down, odd = round up */
95 for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
96 tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
97 tsegall = 1 + tseg / 2;
98 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
99 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
100 /* chose brp step which is possible in system */
101 brp = (brp / btc->brp_inc) * btc->brp_inc;
102 if ((brp < btc->brp_min) || (brp > btc->brp_max))
103 continue;
104 rate = priv->clock.freq / (brp * tsegall);
105 error = bt->bitrate - rate;
106 /* tseg brp biterror */
107 if (error < 0)
108 error = -error;
109 if (error > best_error)
110 continue;
111 best_error = error;
112 if (error == 0) {
113 spt = can_update_spt(btc, sampl_pt, tseg / 2,
114 &tseg1, &tseg2);
115 error = sampl_pt - spt;
116 if (error < 0)
117 error = -error;
118 if (error > spt_error)
119 continue;
120 spt_error = error;
121 }
122 best_tseg = tseg / 2;
123 best_brp = brp;
124 best_rate = rate;
125 if (error == 0)
126 break;
127 }
128
129 if (best_error) {
130 /* Error in one-tenth of a percent */
131 error = (best_error * 1000) / bt->bitrate;
132 if (error > CAN_CALC_MAX_ERROR) {
133 netdev_err(dev,
134 "bitrate error %ld.%ld%% too high\n",
135 error / 10, error % 10);
136 return -EDOM;
137 } else {
138 netdev_warn(dev, "bitrate error %ld.%ld%%\n",
139 error / 10, error % 10);
140 }
141 }
142
143 /* real sample point */
144 bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg,
145 &tseg1, &tseg2);
146
147 v64 = (u64)best_brp * 1000000000UL;
148 do_div(v64, priv->clock.freq);
149 bt->tq = (u32)v64;
150 bt->prop_seg = tseg1 / 2;
151 bt->phase_seg1 = tseg1 - bt->prop_seg;
152 bt->phase_seg2 = tseg2;
153
154 /* check for sjw user settings */
155 if (!bt->sjw || !btc->sjw_max)
156 bt->sjw = 1;
157 else {
158 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
159 if (bt->sjw > btc->sjw_max)
160 bt->sjw = btc->sjw_max;
161 /* bt->sjw must not be higher than tseg2 */
162 if (tseg2 < bt->sjw)
163 bt->sjw = tseg2;
164 }
165
166 bt->brp = best_brp;
167 /* real bit-rate */
168 bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));
169
170 return 0;
171}
172#else /* !CONFIG_CAN_CALC_BITTIMING */
173static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt)
174{
175 netdev_err(dev, "bit-timing calculation not available\n");
176 return -EINVAL;
177}
178#endif /* CONFIG_CAN_CALC_BITTIMING */
179
180/*
181 * Checks the validity of the specified bit-timing parameters prop_seg,
182 * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
183 * prescaler value brp. You can find more information in the header
184 * file linux/can/netlink.h.
185 */
186static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt)
187{
188 struct can_priv *priv = netdev_priv(dev);
189 const struct can_bittiming_const *btc = priv->bittiming_const;
190 int tseg1, alltseg;
191 u64 brp64;
192
193 if (!priv->bittiming_const)
194 return -ENOTSUPP;
195
196 tseg1 = bt->prop_seg + bt->phase_seg1;
197 if (!bt->sjw)
198 bt->sjw = 1;
199 if (bt->sjw > btc->sjw_max ||
200 tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
201 bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
202 return -ERANGE;
203
204 brp64 = (u64)priv->clock.freq * (u64)bt->tq;
205 if (btc->brp_inc > 1)
206 do_div(brp64, btc->brp_inc);
207 brp64 += 500000000UL - 1;
208 do_div(brp64, 1000000000UL); /* the practicable BRP */
209 if (btc->brp_inc > 1)
210 brp64 *= btc->brp_inc;
211 bt->brp = (u32)brp64;
212
213 if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
214 return -EINVAL;
215
216 alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
217 bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
218 bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
219
220 return 0;
221}
222
223static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt)
224{
225 struct can_priv *priv = netdev_priv(dev);
226 int err;
227
228 /* Check if the CAN device has bit-timing parameters */
229 if (priv->bittiming_const) {
230
231 /* Non-expert mode? Check if the bitrate has been pre-defined */
232 if (!bt->tq)
233 /* Determine bit-timing parameters */
234 err = can_calc_bittiming(dev, bt);
235 else
236 /* Check bit-timing params and calculate proper brp */
237 err = can_fixup_bittiming(dev, bt);
238 if (err)
239 return err;
240 }
241
242 return 0;
243}
244
245/*
246 * Local echo of CAN messages
247 *
248 * CAN network devices *should* support a local echo functionality
249 * (see Documentation/networking/can.txt). To test the handling of CAN
250 * interfaces that do not support the local echo both driver types are
251 * implemented. In the case that the driver does not support the echo
252 * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
253 * to perform the echo as a fallback solution.
254 */
255static void can_flush_echo_skb(struct net_device *dev)
256{
257 struct can_priv *priv = netdev_priv(dev);
258 struct net_device_stats *stats = &dev->stats;
259 int i;
260
261 for (i = 0; i < priv->echo_skb_max; i++) {
262 if (priv->echo_skb[i]) {
263 kfree_skb(priv->echo_skb[i]);
264 priv->echo_skb[i] = NULL;
265 stats->tx_dropped++;
266 stats->tx_aborted_errors++;
267 }
268 }
269}
270
271/*
272 * Put the skb on the stack to be looped backed locally lateron
273 *
274 * The function is typically called in the start_xmit function
275 * of the device driver. The driver must protect access to
276 * priv->echo_skb, if necessary.
277 */
278void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
279 unsigned int idx)
280{
281 struct can_priv *priv = netdev_priv(dev);
282
283 BUG_ON(idx >= priv->echo_skb_max);
284
285 /* check flag whether this packet has to be looped back */
286 if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK) {
287 kfree_skb(skb);
288 return;
289 }
290
291 if (!priv->echo_skb[idx]) {
292 struct sock *srcsk = skb->sk;
293
294 if (atomic_read(&skb->users) != 1) {
295 struct sk_buff *old_skb = skb;
296
297 skb = skb_clone(old_skb, GFP_ATOMIC);
298 kfree_skb(old_skb);
299 if (!skb)
300 return;
301 } else
302 skb_orphan(skb);
303
304 skb->sk = srcsk;
305
306 /* make settings for echo to reduce code in irq context */
307 skb->protocol = htons(ETH_P_CAN);
308 skb->pkt_type = PACKET_BROADCAST;
309 skb->ip_summed = CHECKSUM_UNNECESSARY;
310 skb->dev = dev;
311
312 /* save this skb for tx interrupt echo handling */
313 priv->echo_skb[idx] = skb;
314 } else {
315 /* locking problem with netif_stop_queue() ?? */
316 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
317 kfree_skb(skb);
318 }
319}
320EXPORT_SYMBOL_GPL(can_put_echo_skb);
321
322/*
323 * Get the skb from the stack and loop it back locally
324 *
325 * The function is typically called when the TX done interrupt
326 * is handled in the device driver. The driver must protect
327 * access to priv->echo_skb, if necessary.
328 */
329unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
330{
331 struct can_priv *priv = netdev_priv(dev);
332
333 BUG_ON(idx >= priv->echo_skb_max);
334
335 if (priv->echo_skb[idx]) {
336 struct sk_buff *skb = priv->echo_skb[idx];
337 struct can_frame *cf = (struct can_frame *)skb->data;
338 u8 dlc = cf->can_dlc;
339
340 netif_rx(priv->echo_skb[idx]);
341 priv->echo_skb[idx] = NULL;
342
343 return dlc;
344 }
345
346 return 0;
347}
348EXPORT_SYMBOL_GPL(can_get_echo_skb);
349
350/*
351 * Remove the skb from the stack and free it.
352 *
353 * The function is typically called when TX failed.
354 */
355void can_free_echo_skb(struct net_device *dev, unsigned int idx)
356{
357 struct can_priv *priv = netdev_priv(dev);
358
359 BUG_ON(idx >= priv->echo_skb_max);
360
361 if (priv->echo_skb[idx]) {
362 kfree_skb(priv->echo_skb[idx]);
363 priv->echo_skb[idx] = NULL;
364 }
365}
366EXPORT_SYMBOL_GPL(can_free_echo_skb);
367
368/*
369 * CAN device restart for bus-off recovery
370 */
371void can_restart(unsigned long data)
372{
373 struct net_device *dev = (struct net_device *)data;
374 struct can_priv *priv = netdev_priv(dev);
375 struct net_device_stats *stats = &dev->stats;
376 struct sk_buff *skb;
377 struct can_frame *cf;
378 int err;
379
380 BUG_ON(netif_carrier_ok(dev));
381
382 /*
383 * No synchronization needed because the device is bus-off and
384 * no messages can come in or go out.
385 */
386 can_flush_echo_skb(dev);
387
388 /* send restart message upstream */
389 skb = alloc_can_err_skb(dev, &cf);
390 if (skb == NULL) {
391 err = -ENOMEM;
392 goto restart;
393 }
394 cf->can_id |= CAN_ERR_RESTARTED;
395
396 netif_rx(skb);
397
398 stats->rx_packets++;
399 stats->rx_bytes += cf->can_dlc;
400
401restart:
402 netdev_dbg(dev, "restarted\n");
403 priv->can_stats.restarts++;
404
405 /* Now restart the device */
406 err = priv->do_set_mode(dev, CAN_MODE_START);
407
408 netif_carrier_on(dev);
409 if (err)
410 netdev_err(dev, "Error %d during restart", err);
411}
412
413int can_restart_now(struct net_device *dev)
414{
415 struct can_priv *priv = netdev_priv(dev);
416
417 /*
418 * A manual restart is only permitted if automatic restart is
419 * disabled and the device is in the bus-off state
420 */
421 if (priv->restart_ms)
422 return -EINVAL;
423 if (priv->state != CAN_STATE_BUS_OFF)
424 return -EBUSY;
425
426 /* Runs as soon as possible in the timer context */
427 mod_timer(&priv->restart_timer, jiffies);
428
429 return 0;
430}
431
432/*
433 * CAN bus-off
434 *
435 * This functions should be called when the device goes bus-off to
436 * tell the netif layer that no more packets can be sent or received.
437 * If enabled, a timer is started to trigger bus-off recovery.
438 */
439void can_bus_off(struct net_device *dev)
440{
441 struct can_priv *priv = netdev_priv(dev);
442
443 netdev_dbg(dev, "bus-off\n");
444
445 netif_carrier_off(dev);
446 priv->can_stats.bus_off++;
447
448 if (priv->restart_ms)
449 mod_timer(&priv->restart_timer,
450 jiffies + (priv->restart_ms * HZ) / 1000);
451}
452EXPORT_SYMBOL_GPL(can_bus_off);
453
454static void can_setup(struct net_device *dev)
455{
456 dev->type = ARPHRD_CAN;
457 dev->mtu = sizeof(struct can_frame);
458 dev->hard_header_len = 0;
459 dev->addr_len = 0;
460 dev->tx_queue_len = 10;
461
462 /* New-style flags. */
463 dev->flags = IFF_NOARP;
464 dev->features = NETIF_F_HW_CSUM;
465}
466
467struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
468{
469 struct sk_buff *skb;
470
471 skb = netdev_alloc_skb(dev, sizeof(struct can_frame));
472 if (unlikely(!skb))
473 return NULL;
474
475 skb->protocol = htons(ETH_P_CAN);
476 skb->pkt_type = PACKET_BROADCAST;
477 skb->ip_summed = CHECKSUM_UNNECESSARY;
478 *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
479 memset(*cf, 0, sizeof(struct can_frame));
480
481 return skb;
482}
483EXPORT_SYMBOL_GPL(alloc_can_skb);
484
485struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
486{
487 struct sk_buff *skb;
488
489 skb = alloc_can_skb(dev, cf);
490 if (unlikely(!skb))
491 return NULL;
492
493 (*cf)->can_id = CAN_ERR_FLAG;
494 (*cf)->can_dlc = CAN_ERR_DLC;
495
496 return skb;
497}
498EXPORT_SYMBOL_GPL(alloc_can_err_skb);
499
500/*
501 * Allocate and setup space for the CAN network device
502 */
503struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
504{
505 struct net_device *dev;
506 struct can_priv *priv;
507 int size;
508
509 if (echo_skb_max)
510 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
511 echo_skb_max * sizeof(struct sk_buff *);
512 else
513 size = sizeof_priv;
514
515 dev = alloc_netdev(size, "can%d", can_setup);
516 if (!dev)
517 return NULL;
518
519 priv = netdev_priv(dev);
520
521 if (echo_skb_max) {
522 priv->echo_skb_max = echo_skb_max;
523 priv->echo_skb = (void *)priv +
524 ALIGN(sizeof_priv, sizeof(struct sk_buff *));
525 }
526
527 priv->state = CAN_STATE_STOPPED;
528
529 init_timer(&priv->restart_timer);
530
531 return dev;
532}
533EXPORT_SYMBOL_GPL(alloc_candev);
534
535/*
536 * Free space of the CAN network device
537 */
538void free_candev(struct net_device *dev)
539{
540 free_netdev(dev);
541}
542EXPORT_SYMBOL_GPL(free_candev);
543
544/*
545 * Common open function when the device gets opened.
546 *
547 * This function should be called in the open function of the device
548 * driver.
549 */
550int open_candev(struct net_device *dev)
551{
552 struct can_priv *priv = netdev_priv(dev);
553
554 if (!priv->bittiming.tq && !priv->bittiming.bitrate) {
555 netdev_err(dev, "bit-timing not yet defined\n");
556 return -EINVAL;
557 }
558
559 /* Switch carrier on if device was stopped while in bus-off state */
560 if (!netif_carrier_ok(dev))
561 netif_carrier_on(dev);
562
563 setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
564
565 return 0;
566}
567EXPORT_SYMBOL_GPL(open_candev);
568
569/*
570 * Common close function for cleanup before the device gets closed.
571 *
572 * This function should be called in the close function of the device
573 * driver.
574 */
575void close_candev(struct net_device *dev)
576{
577 struct can_priv *priv = netdev_priv(dev);
578
579 if (del_timer_sync(&priv->restart_timer))
580 dev_put(dev);
581 can_flush_echo_skb(dev);
582}
583EXPORT_SYMBOL_GPL(close_candev);
584
585/*
586 * CAN netlink interface
587 */
588static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
589 [IFLA_CAN_STATE] = { .type = NLA_U32 },
590 [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
591 [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
592 [IFLA_CAN_RESTART] = { .type = NLA_U32 },
593 [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
594 [IFLA_CAN_BITTIMING_CONST]
595 = { .len = sizeof(struct can_bittiming_const) },
596 [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
597 [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
598};
599
600static int can_changelink(struct net_device *dev,
601 struct nlattr *tb[], struct nlattr *data[])
602{
603 struct can_priv *priv = netdev_priv(dev);
604 int err;
605
606 /* We need synchronization with dev->stop() */
607 ASSERT_RTNL();
608
609 if (data[IFLA_CAN_CTRLMODE]) {
610 struct can_ctrlmode *cm;
611
612 /* Do not allow changing controller mode while running */
613 if (dev->flags & IFF_UP)
614 return -EBUSY;
615 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
616 if (cm->flags & ~priv->ctrlmode_supported)
617 return -EOPNOTSUPP;
618 priv->ctrlmode &= ~cm->mask;
619 priv->ctrlmode |= cm->flags;
620 }
621
622 if (data[IFLA_CAN_BITTIMING]) {
623 struct can_bittiming bt;
624
625 /* Do not allow changing bittiming while running */
626 if (dev->flags & IFF_UP)
627 return -EBUSY;
628 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
629 if ((!bt.bitrate && !bt.tq) || (bt.bitrate && bt.tq))
630 return -EINVAL;
631 err = can_get_bittiming(dev, &bt);
632 if (err)
633 return err;
634 memcpy(&priv->bittiming, &bt, sizeof(bt));
635
636 if (priv->do_set_bittiming) {
637 /* Finally, set the bit-timing registers */
638 err = priv->do_set_bittiming(dev);
639 if (err)
640 return err;
641 }
642 }
643
644 if (data[IFLA_CAN_RESTART_MS]) {
645 /* Do not allow changing restart delay while running */
646 if (dev->flags & IFF_UP)
647 return -EBUSY;
648 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
649 }
650
651 if (data[IFLA_CAN_RESTART]) {
652 /* Do not allow a restart while not running */
653 if (!(dev->flags & IFF_UP))
654 return -EINVAL;
655 err = can_restart_now(dev);
656 if (err)
657 return err;
658 }
659
660 return 0;
661}
662
663static size_t can_get_size(const struct net_device *dev)
664{
665 struct can_priv *priv = netdev_priv(dev);
666 size_t size;
667
668 size = nla_total_size(sizeof(u32)); /* IFLA_CAN_STATE */
669 size += sizeof(struct can_ctrlmode); /* IFLA_CAN_CTRLMODE */
670 size += nla_total_size(sizeof(u32)); /* IFLA_CAN_RESTART_MS */
671 size += sizeof(struct can_bittiming); /* IFLA_CAN_BITTIMING */
672 size += sizeof(struct can_clock); /* IFLA_CAN_CLOCK */
673 if (priv->do_get_berr_counter) /* IFLA_CAN_BERR_COUNTER */
674 size += sizeof(struct can_berr_counter);
675 if (priv->bittiming_const) /* IFLA_CAN_BITTIMING_CONST */
676 size += sizeof(struct can_bittiming_const);
677
678 return size;
679}
680
681static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
682{
683 struct can_priv *priv = netdev_priv(dev);
684 struct can_ctrlmode cm = {.flags = priv->ctrlmode};
685 struct can_berr_counter bec;
686 enum can_state state = priv->state;
687
688 if (priv->do_get_state)
689 priv->do_get_state(dev, &state);
690 if (nla_put_u32(skb, IFLA_CAN_STATE, state) ||
691 nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
692 nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
693 nla_put(skb, IFLA_CAN_BITTIMING,
694 sizeof(priv->bittiming), &priv->bittiming) ||
695 nla_put(skb, IFLA_CAN_CLOCK, sizeof(cm), &priv->clock) ||
696 (priv->do_get_berr_counter &&
697 !priv->do_get_berr_counter(dev, &bec) &&
698 nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
699 (priv->bittiming_const &&
700 nla_put(skb, IFLA_CAN_BITTIMING_CONST,
701 sizeof(*priv->bittiming_const), priv->bittiming_const)))
702 goto nla_put_failure;
703 return 0;
704
705nla_put_failure:
706 return -EMSGSIZE;
707}
708
709static size_t can_get_xstats_size(const struct net_device *dev)
710{
711 return sizeof(struct can_device_stats);
712}
713
714static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
715{
716 struct can_priv *priv = netdev_priv(dev);
717
718 if (nla_put(skb, IFLA_INFO_XSTATS,
719 sizeof(priv->can_stats), &priv->can_stats))
720 goto nla_put_failure;
721 return 0;
722
723nla_put_failure:
724 return -EMSGSIZE;
725}
726
727static int can_newlink(struct net *src_net, struct net_device *dev,
728 struct nlattr *tb[], struct nlattr *data[])
729{
730 return -EOPNOTSUPP;
731}
732
733static struct rtnl_link_ops can_link_ops __read_mostly = {
734 .kind = "can",
735 .maxtype = IFLA_CAN_MAX,
736 .policy = can_policy,
737 .setup = can_setup,
738 .newlink = can_newlink,
739 .changelink = can_changelink,
740 .get_size = can_get_size,
741 .fill_info = can_fill_info,
742 .get_xstats_size = can_get_xstats_size,
743 .fill_xstats = can_fill_xstats,
744};
745
746/*
747 * Register the CAN network device
748 */
749int register_candev(struct net_device *dev)
750{
751 dev->rtnl_link_ops = &can_link_ops;
752 return register_netdev(dev);
753}
754EXPORT_SYMBOL_GPL(register_candev);
755
756/*
757 * Unregister the CAN network device
758 */
759void unregister_candev(struct net_device *dev)
760{
761 unregister_netdev(dev);
762}
763EXPORT_SYMBOL_GPL(unregister_candev);
764
765static __init int can_dev_init(void)
766{
767 int err;
768
769 err = rtnl_link_register(&can_link_ops);
770 if (!err)
771 printk(KERN_INFO MOD_DESC "\n");
772
773 return err;
774}
775module_init(can_dev_init);
776
777static __exit void can_dev_exit(void)
778{
779 rtnl_link_unregister(&can_link_ops);
780}
781module_exit(can_dev_exit);
782
783MODULE_ALIAS_RTNL_LINK("can");
1/*
2 * Copyright (C) 2005 Marc Kleine-Budde, Pengutronix
3 * Copyright (C) 2006 Andrey Volkov, Varma Electronics
4 * Copyright (C) 2008-2009 Wolfgang Grandegger <wg@grandegger.com>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the version 2 of the GNU General Public License
8 * as published by the Free Software Foundation
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, see <http://www.gnu.org/licenses/>.
17 */
18
19#include <linux/module.h>
20#include <linux/kernel.h>
21#include <linux/slab.h>
22#include <linux/netdevice.h>
23#include <linux/if_arp.h>
24#include <linux/can.h>
25#include <linux/can/dev.h>
26#include <linux/can/skb.h>
27#include <linux/can/netlink.h>
28#include <linux/can/led.h>
29#include <net/rtnetlink.h>
30
31#define MOD_DESC "CAN device driver interface"
32
33MODULE_DESCRIPTION(MOD_DESC);
34MODULE_LICENSE("GPL v2");
35MODULE_AUTHOR("Wolfgang Grandegger <wg@grandegger.com>");
36
37/* CAN DLC to real data length conversion helpers */
38
39static const u8 dlc2len[] = {0, 1, 2, 3, 4, 5, 6, 7,
40 8, 12, 16, 20, 24, 32, 48, 64};
41
42/* get data length from can_dlc with sanitized can_dlc */
43u8 can_dlc2len(u8 can_dlc)
44{
45 return dlc2len[can_dlc & 0x0F];
46}
47EXPORT_SYMBOL_GPL(can_dlc2len);
48
49static const u8 len2dlc[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, /* 0 - 8 */
50 9, 9, 9, 9, /* 9 - 12 */
51 10, 10, 10, 10, /* 13 - 16 */
52 11, 11, 11, 11, /* 17 - 20 */
53 12, 12, 12, 12, /* 21 - 24 */
54 13, 13, 13, 13, 13, 13, 13, 13, /* 25 - 32 */
55 14, 14, 14, 14, 14, 14, 14, 14, /* 33 - 40 */
56 14, 14, 14, 14, 14, 14, 14, 14, /* 41 - 48 */
57 15, 15, 15, 15, 15, 15, 15, 15, /* 49 - 56 */
58 15, 15, 15, 15, 15, 15, 15, 15}; /* 57 - 64 */
59
60/* map the sanitized data length to an appropriate data length code */
61u8 can_len2dlc(u8 len)
62{
63 if (unlikely(len > 64))
64 return 0xF;
65
66 return len2dlc[len];
67}
68EXPORT_SYMBOL_GPL(can_len2dlc);
69
70#ifdef CONFIG_CAN_CALC_BITTIMING
71#define CAN_CALC_MAX_ERROR 50 /* in one-tenth of a percent */
72
73/*
74 * Bit-timing calculation derived from:
75 *
76 * Code based on LinCAN sources and H8S2638 project
77 * Copyright 2004-2006 Pavel Pisa - DCE FELK CVUT cz
78 * Copyright 2005 Stanislav Marek
79 * email: pisa@cmp.felk.cvut.cz
80 *
81 * Calculates proper bit-timing parameters for a specified bit-rate
82 * and sample-point, which can then be used to set the bit-timing
83 * registers of the CAN controller. You can find more information
84 * in the header file linux/can/netlink.h.
85 */
86static int can_update_spt(const struct can_bittiming_const *btc,
87 int sampl_pt, int tseg, int *tseg1, int *tseg2)
88{
89 *tseg2 = tseg + 1 - (sampl_pt * (tseg + 1)) / 1000;
90 if (*tseg2 < btc->tseg2_min)
91 *tseg2 = btc->tseg2_min;
92 if (*tseg2 > btc->tseg2_max)
93 *tseg2 = btc->tseg2_max;
94 *tseg1 = tseg - *tseg2;
95 if (*tseg1 > btc->tseg1_max) {
96 *tseg1 = btc->tseg1_max;
97 *tseg2 = tseg - *tseg1;
98 }
99 return 1000 * (tseg + 1 - *tseg2) / (tseg + 1);
100}
101
102static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
103 const struct can_bittiming_const *btc)
104{
105 struct can_priv *priv = netdev_priv(dev);
106 long best_error = 1000000000, error = 0;
107 int best_tseg = 0, best_brp = 0, brp = 0;
108 int tsegall, tseg = 0, tseg1 = 0, tseg2 = 0;
109 int spt_error = 1000, spt = 0, sampl_pt;
110 long rate;
111 u64 v64;
112
113 /* Use CiA recommended sample points */
114 if (bt->sample_point) {
115 sampl_pt = bt->sample_point;
116 } else {
117 if (bt->bitrate > 800000)
118 sampl_pt = 750;
119 else if (bt->bitrate > 500000)
120 sampl_pt = 800;
121 else
122 sampl_pt = 875;
123 }
124
125 /* tseg even = round down, odd = round up */
126 for (tseg = (btc->tseg1_max + btc->tseg2_max) * 2 + 1;
127 tseg >= (btc->tseg1_min + btc->tseg2_min) * 2; tseg--) {
128 tsegall = 1 + tseg / 2;
129 /* Compute all possible tseg choices (tseg=tseg1+tseg2) */
130 brp = priv->clock.freq / (tsegall * bt->bitrate) + tseg % 2;
131 /* chose brp step which is possible in system */
132 brp = (brp / btc->brp_inc) * btc->brp_inc;
133 if ((brp < btc->brp_min) || (brp > btc->brp_max))
134 continue;
135 rate = priv->clock.freq / (brp * tsegall);
136 error = bt->bitrate - rate;
137 /* tseg brp biterror */
138 if (error < 0)
139 error = -error;
140 if (error > best_error)
141 continue;
142 best_error = error;
143 if (error == 0) {
144 spt = can_update_spt(btc, sampl_pt, tseg / 2,
145 &tseg1, &tseg2);
146 error = sampl_pt - spt;
147 if (error < 0)
148 error = -error;
149 if (error > spt_error)
150 continue;
151 spt_error = error;
152 }
153 best_tseg = tseg / 2;
154 best_brp = brp;
155 if (error == 0)
156 break;
157 }
158
159 if (best_error) {
160 /* Error in one-tenth of a percent */
161 error = (best_error * 1000) / bt->bitrate;
162 if (error > CAN_CALC_MAX_ERROR) {
163 netdev_err(dev,
164 "bitrate error %ld.%ld%% too high\n",
165 error / 10, error % 10);
166 return -EDOM;
167 } else {
168 netdev_warn(dev, "bitrate error %ld.%ld%%\n",
169 error / 10, error % 10);
170 }
171 }
172
173 /* real sample point */
174 bt->sample_point = can_update_spt(btc, sampl_pt, best_tseg,
175 &tseg1, &tseg2);
176
177 v64 = (u64)best_brp * 1000000000UL;
178 do_div(v64, priv->clock.freq);
179 bt->tq = (u32)v64;
180 bt->prop_seg = tseg1 / 2;
181 bt->phase_seg1 = tseg1 - bt->prop_seg;
182 bt->phase_seg2 = tseg2;
183
184 /* check for sjw user settings */
185 if (!bt->sjw || !btc->sjw_max)
186 bt->sjw = 1;
187 else {
188 /* bt->sjw is at least 1 -> sanitize upper bound to sjw_max */
189 if (bt->sjw > btc->sjw_max)
190 bt->sjw = btc->sjw_max;
191 /* bt->sjw must not be higher than tseg2 */
192 if (tseg2 < bt->sjw)
193 bt->sjw = tseg2;
194 }
195
196 bt->brp = best_brp;
197 /* real bit-rate */
198 bt->bitrate = priv->clock.freq / (bt->brp * (tseg1 + tseg2 + 1));
199
200 return 0;
201}
202#else /* !CONFIG_CAN_CALC_BITTIMING */
203static int can_calc_bittiming(struct net_device *dev, struct can_bittiming *bt,
204 const struct can_bittiming_const *btc)
205{
206 netdev_err(dev, "bit-timing calculation not available\n");
207 return -EINVAL;
208}
209#endif /* CONFIG_CAN_CALC_BITTIMING */
210
211/*
212 * Checks the validity of the specified bit-timing parameters prop_seg,
213 * phase_seg1, phase_seg2 and sjw and tries to determine the bitrate
214 * prescaler value brp. You can find more information in the header
215 * file linux/can/netlink.h.
216 */
217static int can_fixup_bittiming(struct net_device *dev, struct can_bittiming *bt,
218 const struct can_bittiming_const *btc)
219{
220 struct can_priv *priv = netdev_priv(dev);
221 int tseg1, alltseg;
222 u64 brp64;
223
224 tseg1 = bt->prop_seg + bt->phase_seg1;
225 if (!bt->sjw)
226 bt->sjw = 1;
227 if (bt->sjw > btc->sjw_max ||
228 tseg1 < btc->tseg1_min || tseg1 > btc->tseg1_max ||
229 bt->phase_seg2 < btc->tseg2_min || bt->phase_seg2 > btc->tseg2_max)
230 return -ERANGE;
231
232 brp64 = (u64)priv->clock.freq * (u64)bt->tq;
233 if (btc->brp_inc > 1)
234 do_div(brp64, btc->brp_inc);
235 brp64 += 500000000UL - 1;
236 do_div(brp64, 1000000000UL); /* the practicable BRP */
237 if (btc->brp_inc > 1)
238 brp64 *= btc->brp_inc;
239 bt->brp = (u32)brp64;
240
241 if (bt->brp < btc->brp_min || bt->brp > btc->brp_max)
242 return -EINVAL;
243
244 alltseg = bt->prop_seg + bt->phase_seg1 + bt->phase_seg2 + 1;
245 bt->bitrate = priv->clock.freq / (bt->brp * alltseg);
246 bt->sample_point = ((tseg1 + 1) * 1000) / alltseg;
247
248 return 0;
249}
250
251static int can_get_bittiming(struct net_device *dev, struct can_bittiming *bt,
252 const struct can_bittiming_const *btc)
253{
254 int err;
255
256 /* Check if the CAN device has bit-timing parameters */
257 if (!btc)
258 return -EOPNOTSUPP;
259
260 /*
261 * Depending on the given can_bittiming parameter structure the CAN
262 * timing parameters are calculated based on the provided bitrate OR
263 * alternatively the CAN timing parameters (tq, prop_seg, etc.) are
264 * provided directly which are then checked and fixed up.
265 */
266 if (!bt->tq && bt->bitrate)
267 err = can_calc_bittiming(dev, bt, btc);
268 else if (bt->tq && !bt->bitrate)
269 err = can_fixup_bittiming(dev, bt, btc);
270 else
271 err = -EINVAL;
272
273 return err;
274}
275
276static void can_update_state_error_stats(struct net_device *dev,
277 enum can_state new_state)
278{
279 struct can_priv *priv = netdev_priv(dev);
280
281 if (new_state <= priv->state)
282 return;
283
284 switch (new_state) {
285 case CAN_STATE_ERROR_WARNING:
286 priv->can_stats.error_warning++;
287 break;
288 case CAN_STATE_ERROR_PASSIVE:
289 priv->can_stats.error_passive++;
290 break;
291 case CAN_STATE_BUS_OFF:
292 priv->can_stats.bus_off++;
293 break;
294 default:
295 break;
296 }
297}
298
299static int can_tx_state_to_frame(struct net_device *dev, enum can_state state)
300{
301 switch (state) {
302 case CAN_STATE_ERROR_ACTIVE:
303 return CAN_ERR_CRTL_ACTIVE;
304 case CAN_STATE_ERROR_WARNING:
305 return CAN_ERR_CRTL_TX_WARNING;
306 case CAN_STATE_ERROR_PASSIVE:
307 return CAN_ERR_CRTL_TX_PASSIVE;
308 default:
309 return 0;
310 }
311}
312
313static int can_rx_state_to_frame(struct net_device *dev, enum can_state state)
314{
315 switch (state) {
316 case CAN_STATE_ERROR_ACTIVE:
317 return CAN_ERR_CRTL_ACTIVE;
318 case CAN_STATE_ERROR_WARNING:
319 return CAN_ERR_CRTL_RX_WARNING;
320 case CAN_STATE_ERROR_PASSIVE:
321 return CAN_ERR_CRTL_RX_PASSIVE;
322 default:
323 return 0;
324 }
325}
326
327void can_change_state(struct net_device *dev, struct can_frame *cf,
328 enum can_state tx_state, enum can_state rx_state)
329{
330 struct can_priv *priv = netdev_priv(dev);
331 enum can_state new_state = max(tx_state, rx_state);
332
333 if (unlikely(new_state == priv->state)) {
334 netdev_warn(dev, "%s: oops, state did not change", __func__);
335 return;
336 }
337
338 netdev_dbg(dev, "New error state: %d\n", new_state);
339
340 can_update_state_error_stats(dev, new_state);
341 priv->state = new_state;
342
343 if (unlikely(new_state == CAN_STATE_BUS_OFF)) {
344 cf->can_id |= CAN_ERR_BUSOFF;
345 return;
346 }
347
348 cf->can_id |= CAN_ERR_CRTL;
349 cf->data[1] |= tx_state >= rx_state ?
350 can_tx_state_to_frame(dev, tx_state) : 0;
351 cf->data[1] |= tx_state <= rx_state ?
352 can_rx_state_to_frame(dev, rx_state) : 0;
353}
354EXPORT_SYMBOL_GPL(can_change_state);
355
356/*
357 * Local echo of CAN messages
358 *
359 * CAN network devices *should* support a local echo functionality
360 * (see Documentation/networking/can.txt). To test the handling of CAN
361 * interfaces that do not support the local echo both driver types are
362 * implemented. In the case that the driver does not support the echo
363 * the IFF_ECHO remains clear in dev->flags. This causes the PF_CAN core
364 * to perform the echo as a fallback solution.
365 */
366static void can_flush_echo_skb(struct net_device *dev)
367{
368 struct can_priv *priv = netdev_priv(dev);
369 struct net_device_stats *stats = &dev->stats;
370 int i;
371
372 for (i = 0; i < priv->echo_skb_max; i++) {
373 if (priv->echo_skb[i]) {
374 kfree_skb(priv->echo_skb[i]);
375 priv->echo_skb[i] = NULL;
376 stats->tx_dropped++;
377 stats->tx_aborted_errors++;
378 }
379 }
380}
381
382/*
383 * Put the skb on the stack to be looped backed locally lateron
384 *
385 * The function is typically called in the start_xmit function
386 * of the device driver. The driver must protect access to
387 * priv->echo_skb, if necessary.
388 */
389void can_put_echo_skb(struct sk_buff *skb, struct net_device *dev,
390 unsigned int idx)
391{
392 struct can_priv *priv = netdev_priv(dev);
393
394 BUG_ON(idx >= priv->echo_skb_max);
395
396 /* check flag whether this packet has to be looped back */
397 if (!(dev->flags & IFF_ECHO) || skb->pkt_type != PACKET_LOOPBACK ||
398 (skb->protocol != htons(ETH_P_CAN) &&
399 skb->protocol != htons(ETH_P_CANFD))) {
400 kfree_skb(skb);
401 return;
402 }
403
404 if (!priv->echo_skb[idx]) {
405
406 skb = can_create_echo_skb(skb);
407 if (!skb)
408 return;
409
410 /* make settings for echo to reduce code in irq context */
411 skb->pkt_type = PACKET_BROADCAST;
412 skb->ip_summed = CHECKSUM_UNNECESSARY;
413 skb->dev = dev;
414
415 /* save this skb for tx interrupt echo handling */
416 priv->echo_skb[idx] = skb;
417 } else {
418 /* locking problem with netif_stop_queue() ?? */
419 netdev_err(dev, "%s: BUG! echo_skb is occupied!\n", __func__);
420 kfree_skb(skb);
421 }
422}
423EXPORT_SYMBOL_GPL(can_put_echo_skb);
424
425/*
426 * Get the skb from the stack and loop it back locally
427 *
428 * The function is typically called when the TX done interrupt
429 * is handled in the device driver. The driver must protect
430 * access to priv->echo_skb, if necessary.
431 */
432unsigned int can_get_echo_skb(struct net_device *dev, unsigned int idx)
433{
434 struct can_priv *priv = netdev_priv(dev);
435
436 BUG_ON(idx >= priv->echo_skb_max);
437
438 if (priv->echo_skb[idx]) {
439 struct sk_buff *skb = priv->echo_skb[idx];
440 struct can_frame *cf = (struct can_frame *)skb->data;
441 u8 dlc = cf->can_dlc;
442
443 netif_rx(priv->echo_skb[idx]);
444 priv->echo_skb[idx] = NULL;
445
446 return dlc;
447 }
448
449 return 0;
450}
451EXPORT_SYMBOL_GPL(can_get_echo_skb);
452
453/*
454 * Remove the skb from the stack and free it.
455 *
456 * The function is typically called when TX failed.
457 */
458void can_free_echo_skb(struct net_device *dev, unsigned int idx)
459{
460 struct can_priv *priv = netdev_priv(dev);
461
462 BUG_ON(idx >= priv->echo_skb_max);
463
464 if (priv->echo_skb[idx]) {
465 dev_kfree_skb_any(priv->echo_skb[idx]);
466 priv->echo_skb[idx] = NULL;
467 }
468}
469EXPORT_SYMBOL_GPL(can_free_echo_skb);
470
471/*
472 * CAN device restart for bus-off recovery
473 */
474static void can_restart(unsigned long data)
475{
476 struct net_device *dev = (struct net_device *)data;
477 struct can_priv *priv = netdev_priv(dev);
478 struct net_device_stats *stats = &dev->stats;
479 struct sk_buff *skb;
480 struct can_frame *cf;
481 int err;
482
483 BUG_ON(netif_carrier_ok(dev));
484
485 /*
486 * No synchronization needed because the device is bus-off and
487 * no messages can come in or go out.
488 */
489 can_flush_echo_skb(dev);
490
491 /* send restart message upstream */
492 skb = alloc_can_err_skb(dev, &cf);
493 if (skb == NULL) {
494 err = -ENOMEM;
495 goto restart;
496 }
497 cf->can_id |= CAN_ERR_RESTARTED;
498
499 netif_rx(skb);
500
501 stats->rx_packets++;
502 stats->rx_bytes += cf->can_dlc;
503
504restart:
505 netdev_dbg(dev, "restarted\n");
506 priv->can_stats.restarts++;
507
508 /* Now restart the device */
509 err = priv->do_set_mode(dev, CAN_MODE_START);
510
511 netif_carrier_on(dev);
512 if (err)
513 netdev_err(dev, "Error %d during restart", err);
514}
515
516int can_restart_now(struct net_device *dev)
517{
518 struct can_priv *priv = netdev_priv(dev);
519
520 /*
521 * A manual restart is only permitted if automatic restart is
522 * disabled and the device is in the bus-off state
523 */
524 if (priv->restart_ms)
525 return -EINVAL;
526 if (priv->state != CAN_STATE_BUS_OFF)
527 return -EBUSY;
528
529 /* Runs as soon as possible in the timer context */
530 mod_timer(&priv->restart_timer, jiffies);
531
532 return 0;
533}
534
535/*
536 * CAN bus-off
537 *
538 * This functions should be called when the device goes bus-off to
539 * tell the netif layer that no more packets can be sent or received.
540 * If enabled, a timer is started to trigger bus-off recovery.
541 */
542void can_bus_off(struct net_device *dev)
543{
544 struct can_priv *priv = netdev_priv(dev);
545
546 netdev_dbg(dev, "bus-off\n");
547
548 netif_carrier_off(dev);
549
550 if (priv->restart_ms)
551 mod_timer(&priv->restart_timer,
552 jiffies + (priv->restart_ms * HZ) / 1000);
553}
554EXPORT_SYMBOL_GPL(can_bus_off);
555
556static void can_setup(struct net_device *dev)
557{
558 dev->type = ARPHRD_CAN;
559 dev->mtu = CAN_MTU;
560 dev->hard_header_len = 0;
561 dev->addr_len = 0;
562 dev->tx_queue_len = 10;
563
564 /* New-style flags. */
565 dev->flags = IFF_NOARP;
566 dev->features = NETIF_F_HW_CSUM;
567}
568
569struct sk_buff *alloc_can_skb(struct net_device *dev, struct can_frame **cf)
570{
571 struct sk_buff *skb;
572
573 skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
574 sizeof(struct can_frame));
575 if (unlikely(!skb))
576 return NULL;
577
578 skb->protocol = htons(ETH_P_CAN);
579 skb->pkt_type = PACKET_BROADCAST;
580 skb->ip_summed = CHECKSUM_UNNECESSARY;
581
582 skb_reset_mac_header(skb);
583 skb_reset_network_header(skb);
584 skb_reset_transport_header(skb);
585
586 can_skb_reserve(skb);
587 can_skb_prv(skb)->ifindex = dev->ifindex;
588 can_skb_prv(skb)->skbcnt = 0;
589
590 *cf = (struct can_frame *)skb_put(skb, sizeof(struct can_frame));
591 memset(*cf, 0, sizeof(struct can_frame));
592
593 return skb;
594}
595EXPORT_SYMBOL_GPL(alloc_can_skb);
596
597struct sk_buff *alloc_canfd_skb(struct net_device *dev,
598 struct canfd_frame **cfd)
599{
600 struct sk_buff *skb;
601
602 skb = netdev_alloc_skb(dev, sizeof(struct can_skb_priv) +
603 sizeof(struct canfd_frame));
604 if (unlikely(!skb))
605 return NULL;
606
607 skb->protocol = htons(ETH_P_CANFD);
608 skb->pkt_type = PACKET_BROADCAST;
609 skb->ip_summed = CHECKSUM_UNNECESSARY;
610
611 skb_reset_mac_header(skb);
612 skb_reset_network_header(skb);
613 skb_reset_transport_header(skb);
614
615 can_skb_reserve(skb);
616 can_skb_prv(skb)->ifindex = dev->ifindex;
617 can_skb_prv(skb)->skbcnt = 0;
618
619 *cfd = (struct canfd_frame *)skb_put(skb, sizeof(struct canfd_frame));
620 memset(*cfd, 0, sizeof(struct canfd_frame));
621
622 return skb;
623}
624EXPORT_SYMBOL_GPL(alloc_canfd_skb);
625
626struct sk_buff *alloc_can_err_skb(struct net_device *dev, struct can_frame **cf)
627{
628 struct sk_buff *skb;
629
630 skb = alloc_can_skb(dev, cf);
631 if (unlikely(!skb))
632 return NULL;
633
634 (*cf)->can_id = CAN_ERR_FLAG;
635 (*cf)->can_dlc = CAN_ERR_DLC;
636
637 return skb;
638}
639EXPORT_SYMBOL_GPL(alloc_can_err_skb);
640
641/*
642 * Allocate and setup space for the CAN network device
643 */
644struct net_device *alloc_candev(int sizeof_priv, unsigned int echo_skb_max)
645{
646 struct net_device *dev;
647 struct can_priv *priv;
648 int size;
649
650 if (echo_skb_max)
651 size = ALIGN(sizeof_priv, sizeof(struct sk_buff *)) +
652 echo_skb_max * sizeof(struct sk_buff *);
653 else
654 size = sizeof_priv;
655
656 dev = alloc_netdev(size, "can%d", NET_NAME_UNKNOWN, can_setup);
657 if (!dev)
658 return NULL;
659
660 priv = netdev_priv(dev);
661
662 if (echo_skb_max) {
663 priv->echo_skb_max = echo_skb_max;
664 priv->echo_skb = (void *)priv +
665 ALIGN(sizeof_priv, sizeof(struct sk_buff *));
666 }
667
668 priv->state = CAN_STATE_STOPPED;
669
670 init_timer(&priv->restart_timer);
671
672 return dev;
673}
674EXPORT_SYMBOL_GPL(alloc_candev);
675
676/*
677 * Free space of the CAN network device
678 */
679void free_candev(struct net_device *dev)
680{
681 free_netdev(dev);
682}
683EXPORT_SYMBOL_GPL(free_candev);
684
685/*
686 * changing MTU and control mode for CAN/CANFD devices
687 */
688int can_change_mtu(struct net_device *dev, int new_mtu)
689{
690 struct can_priv *priv = netdev_priv(dev);
691
692 /* Do not allow changing the MTU while running */
693 if (dev->flags & IFF_UP)
694 return -EBUSY;
695
696 /* allow change of MTU according to the CANFD ability of the device */
697 switch (new_mtu) {
698 case CAN_MTU:
699 priv->ctrlmode &= ~CAN_CTRLMODE_FD;
700 break;
701
702 case CANFD_MTU:
703 if (!(priv->ctrlmode_supported & CAN_CTRLMODE_FD))
704 return -EINVAL;
705
706 priv->ctrlmode |= CAN_CTRLMODE_FD;
707 break;
708
709 default:
710 return -EINVAL;
711 }
712
713 dev->mtu = new_mtu;
714 return 0;
715}
716EXPORT_SYMBOL_GPL(can_change_mtu);
717
718/*
719 * Common open function when the device gets opened.
720 *
721 * This function should be called in the open function of the device
722 * driver.
723 */
724int open_candev(struct net_device *dev)
725{
726 struct can_priv *priv = netdev_priv(dev);
727
728 if (!priv->bittiming.bitrate) {
729 netdev_err(dev, "bit-timing not yet defined\n");
730 return -EINVAL;
731 }
732
733 /* For CAN FD the data bitrate has to be >= the arbitration bitrate */
734 if ((priv->ctrlmode & CAN_CTRLMODE_FD) &&
735 (!priv->data_bittiming.bitrate ||
736 (priv->data_bittiming.bitrate < priv->bittiming.bitrate))) {
737 netdev_err(dev, "incorrect/missing data bit-timing\n");
738 return -EINVAL;
739 }
740
741 /* Switch carrier on if device was stopped while in bus-off state */
742 if (!netif_carrier_ok(dev))
743 netif_carrier_on(dev);
744
745 setup_timer(&priv->restart_timer, can_restart, (unsigned long)dev);
746
747 return 0;
748}
749EXPORT_SYMBOL_GPL(open_candev);
750
751/*
752 * Common close function for cleanup before the device gets closed.
753 *
754 * This function should be called in the close function of the device
755 * driver.
756 */
757void close_candev(struct net_device *dev)
758{
759 struct can_priv *priv = netdev_priv(dev);
760
761 del_timer_sync(&priv->restart_timer);
762 can_flush_echo_skb(dev);
763}
764EXPORT_SYMBOL_GPL(close_candev);
765
766/*
767 * CAN netlink interface
768 */
769static const struct nla_policy can_policy[IFLA_CAN_MAX + 1] = {
770 [IFLA_CAN_STATE] = { .type = NLA_U32 },
771 [IFLA_CAN_CTRLMODE] = { .len = sizeof(struct can_ctrlmode) },
772 [IFLA_CAN_RESTART_MS] = { .type = NLA_U32 },
773 [IFLA_CAN_RESTART] = { .type = NLA_U32 },
774 [IFLA_CAN_BITTIMING] = { .len = sizeof(struct can_bittiming) },
775 [IFLA_CAN_BITTIMING_CONST]
776 = { .len = sizeof(struct can_bittiming_const) },
777 [IFLA_CAN_CLOCK] = { .len = sizeof(struct can_clock) },
778 [IFLA_CAN_BERR_COUNTER] = { .len = sizeof(struct can_berr_counter) },
779 [IFLA_CAN_DATA_BITTIMING]
780 = { .len = sizeof(struct can_bittiming) },
781 [IFLA_CAN_DATA_BITTIMING_CONST]
782 = { .len = sizeof(struct can_bittiming_const) },
783};
784
785static int can_changelink(struct net_device *dev,
786 struct nlattr *tb[], struct nlattr *data[])
787{
788 struct can_priv *priv = netdev_priv(dev);
789 int err;
790
791 /* We need synchronization with dev->stop() */
792 ASSERT_RTNL();
793
794 if (data[IFLA_CAN_BITTIMING]) {
795 struct can_bittiming bt;
796
797 /* Do not allow changing bittiming while running */
798 if (dev->flags & IFF_UP)
799 return -EBUSY;
800 memcpy(&bt, nla_data(data[IFLA_CAN_BITTIMING]), sizeof(bt));
801 err = can_get_bittiming(dev, &bt, priv->bittiming_const);
802 if (err)
803 return err;
804 memcpy(&priv->bittiming, &bt, sizeof(bt));
805
806 if (priv->do_set_bittiming) {
807 /* Finally, set the bit-timing registers */
808 err = priv->do_set_bittiming(dev);
809 if (err)
810 return err;
811 }
812 }
813
814 if (data[IFLA_CAN_CTRLMODE]) {
815 struct can_ctrlmode *cm;
816
817 /* Do not allow changing controller mode while running */
818 if (dev->flags & IFF_UP)
819 return -EBUSY;
820 cm = nla_data(data[IFLA_CAN_CTRLMODE]);
821
822 /* check whether changed bits are allowed to be modified */
823 if (cm->mask & ~priv->ctrlmode_supported)
824 return -EOPNOTSUPP;
825
826 /* clear bits to be modified and copy the flag values */
827 priv->ctrlmode &= ~cm->mask;
828 priv->ctrlmode |= (cm->flags & cm->mask);
829
830 /* CAN_CTRLMODE_FD can only be set when driver supports FD */
831 if (priv->ctrlmode & CAN_CTRLMODE_FD)
832 dev->mtu = CANFD_MTU;
833 else
834 dev->mtu = CAN_MTU;
835 }
836
837 if (data[IFLA_CAN_RESTART_MS]) {
838 /* Do not allow changing restart delay while running */
839 if (dev->flags & IFF_UP)
840 return -EBUSY;
841 priv->restart_ms = nla_get_u32(data[IFLA_CAN_RESTART_MS]);
842 }
843
844 if (data[IFLA_CAN_RESTART]) {
845 /* Do not allow a restart while not running */
846 if (!(dev->flags & IFF_UP))
847 return -EINVAL;
848 err = can_restart_now(dev);
849 if (err)
850 return err;
851 }
852
853 if (data[IFLA_CAN_DATA_BITTIMING]) {
854 struct can_bittiming dbt;
855
856 /* Do not allow changing bittiming while running */
857 if (dev->flags & IFF_UP)
858 return -EBUSY;
859 memcpy(&dbt, nla_data(data[IFLA_CAN_DATA_BITTIMING]),
860 sizeof(dbt));
861 err = can_get_bittiming(dev, &dbt, priv->data_bittiming_const);
862 if (err)
863 return err;
864 memcpy(&priv->data_bittiming, &dbt, sizeof(dbt));
865
866 if (priv->do_set_data_bittiming) {
867 /* Finally, set the bit-timing registers */
868 err = priv->do_set_data_bittiming(dev);
869 if (err)
870 return err;
871 }
872 }
873
874 return 0;
875}
876
877static size_t can_get_size(const struct net_device *dev)
878{
879 struct can_priv *priv = netdev_priv(dev);
880 size_t size = 0;
881
882 if (priv->bittiming.bitrate) /* IFLA_CAN_BITTIMING */
883 size += nla_total_size(sizeof(struct can_bittiming));
884 if (priv->bittiming_const) /* IFLA_CAN_BITTIMING_CONST */
885 size += nla_total_size(sizeof(struct can_bittiming_const));
886 size += nla_total_size(sizeof(struct can_clock)); /* IFLA_CAN_CLOCK */
887 size += nla_total_size(sizeof(u32)); /* IFLA_CAN_STATE */
888 size += nla_total_size(sizeof(struct can_ctrlmode)); /* IFLA_CAN_CTRLMODE */
889 size += nla_total_size(sizeof(u32)); /* IFLA_CAN_RESTART_MS */
890 if (priv->do_get_berr_counter) /* IFLA_CAN_BERR_COUNTER */
891 size += nla_total_size(sizeof(struct can_berr_counter));
892 if (priv->data_bittiming.bitrate) /* IFLA_CAN_DATA_BITTIMING */
893 size += nla_total_size(sizeof(struct can_bittiming));
894 if (priv->data_bittiming_const) /* IFLA_CAN_DATA_BITTIMING_CONST */
895 size += nla_total_size(sizeof(struct can_bittiming_const));
896
897 return size;
898}
899
900static int can_fill_info(struct sk_buff *skb, const struct net_device *dev)
901{
902 struct can_priv *priv = netdev_priv(dev);
903 struct can_ctrlmode cm = {.flags = priv->ctrlmode};
904 struct can_berr_counter bec;
905 enum can_state state = priv->state;
906
907 if (priv->do_get_state)
908 priv->do_get_state(dev, &state);
909
910 if ((priv->bittiming.bitrate &&
911 nla_put(skb, IFLA_CAN_BITTIMING,
912 sizeof(priv->bittiming), &priv->bittiming)) ||
913
914 (priv->bittiming_const &&
915 nla_put(skb, IFLA_CAN_BITTIMING_CONST,
916 sizeof(*priv->bittiming_const), priv->bittiming_const)) ||
917
918 nla_put(skb, IFLA_CAN_CLOCK, sizeof(priv->clock), &priv->clock) ||
919 nla_put_u32(skb, IFLA_CAN_STATE, state) ||
920 nla_put(skb, IFLA_CAN_CTRLMODE, sizeof(cm), &cm) ||
921 nla_put_u32(skb, IFLA_CAN_RESTART_MS, priv->restart_ms) ||
922
923 (priv->do_get_berr_counter &&
924 !priv->do_get_berr_counter(dev, &bec) &&
925 nla_put(skb, IFLA_CAN_BERR_COUNTER, sizeof(bec), &bec)) ||
926
927 (priv->data_bittiming.bitrate &&
928 nla_put(skb, IFLA_CAN_DATA_BITTIMING,
929 sizeof(priv->data_bittiming), &priv->data_bittiming)) ||
930
931 (priv->data_bittiming_const &&
932 nla_put(skb, IFLA_CAN_DATA_BITTIMING_CONST,
933 sizeof(*priv->data_bittiming_const),
934 priv->data_bittiming_const)))
935 return -EMSGSIZE;
936
937 return 0;
938}
939
940static size_t can_get_xstats_size(const struct net_device *dev)
941{
942 return sizeof(struct can_device_stats);
943}
944
945static int can_fill_xstats(struct sk_buff *skb, const struct net_device *dev)
946{
947 struct can_priv *priv = netdev_priv(dev);
948
949 if (nla_put(skb, IFLA_INFO_XSTATS,
950 sizeof(priv->can_stats), &priv->can_stats))
951 goto nla_put_failure;
952 return 0;
953
954nla_put_failure:
955 return -EMSGSIZE;
956}
957
958static int can_newlink(struct net *src_net, struct net_device *dev,
959 struct nlattr *tb[], struct nlattr *data[])
960{
961 return -EOPNOTSUPP;
962}
963
964static struct rtnl_link_ops can_link_ops __read_mostly = {
965 .kind = "can",
966 .maxtype = IFLA_CAN_MAX,
967 .policy = can_policy,
968 .setup = can_setup,
969 .newlink = can_newlink,
970 .changelink = can_changelink,
971 .get_size = can_get_size,
972 .fill_info = can_fill_info,
973 .get_xstats_size = can_get_xstats_size,
974 .fill_xstats = can_fill_xstats,
975};
976
977/*
978 * Register the CAN network device
979 */
980int register_candev(struct net_device *dev)
981{
982 dev->rtnl_link_ops = &can_link_ops;
983 return register_netdev(dev);
984}
985EXPORT_SYMBOL_GPL(register_candev);
986
987/*
988 * Unregister the CAN network device
989 */
990void unregister_candev(struct net_device *dev)
991{
992 unregister_netdev(dev);
993}
994EXPORT_SYMBOL_GPL(unregister_candev);
995
996/*
997 * Test if a network device is a candev based device
998 * and return the can_priv* if so.
999 */
1000struct can_priv *safe_candev_priv(struct net_device *dev)
1001{
1002 if ((dev->type != ARPHRD_CAN) || (dev->rtnl_link_ops != &can_link_ops))
1003 return NULL;
1004
1005 return netdev_priv(dev);
1006}
1007EXPORT_SYMBOL_GPL(safe_candev_priv);
1008
1009static __init int can_dev_init(void)
1010{
1011 int err;
1012
1013 can_led_notifier_init();
1014
1015 err = rtnl_link_register(&can_link_ops);
1016 if (!err)
1017 printk(KERN_INFO MOD_DESC "\n");
1018
1019 return err;
1020}
1021module_init(can_dev_init);
1022
1023static __exit void can_dev_exit(void)
1024{
1025 rtnl_link_unregister(&can_link_ops);
1026
1027 can_led_notifier_exit();
1028}
1029module_exit(can_dev_exit);
1030
1031MODULE_ALIAS_RTNL_LINK("can");